CVE-2026-55897luci-app-advanced-reboot is a LuCI (web interface) application for OpenWrt that provides a way to reboot your router into an alternative firmware partition or perform reboot operations directly from the web UI. Prior to 1.1.2-6, the luci-app-advanced-reboot read ACL in applications/luci-app-advanced-reboot/root/usr/share/rpcd/acl.d/luci-app-advanced-reboot.json grants rpcd file.exec permission for the general shell interpreter /bin/sh. An authenticated delegated session with that read ACL can supply caller-controlled params; rpcd authorizes the executable path and passes those arguments to the shell, allowing arbitrary commands to execute as root. Builds without the /bin/sh exec grant, including the checked openwrt-24.10 and openwrt-23.05 branches, are not affected by this specific chain. This vulnerability is fixed in 1.1.2-6.